1. Field of the Invention
The present invention generally relates to a communications system and, more particularly, to a burst mode optical receiver and system and method therefor.
2. Description of the Related Art
Optical communications systems utilize receivers capable of receiving data continuously transmitted (i.e., in continuous mode) or data transmitted in a burst mode (i.e., a direct unencoded transmission of data wherein the data being transmitted have long strings of only 1s or long strings of only 0s). FIGS. 1A, 1B, 1C and 1D are diagrams illustrating waveforms of data transmission in continuous mode and in burst mode, each with and without direct current (“DC”) offset. In particular, FIGS. 1A and 1B diagrams that illustrate waveforms of data transmission in a continuous mode with and without DC offset, respectively. FIGS. 1C and 1D are diagrams that illustrate waveforms of data transmission in a burst mode with and without DC offset, respectively. Alternating current (“AC”) coupled optical receivers capable of performing continuous data transmission are also employed in conventional communications systems.
DC coupled optical receivers capable of performing burst mode transmission are also employed in conventional communications systems. Data encoding and decoding required in burst mode transmission, however, undesirably increases system complexity and reduces transmission speed. Examples of conventional communications systems utilizing burst mode transmission are illustrated in, e.g., U.S. Pat. Nos. 5,025,456, 5,371,763 and 5,875,050. When digital data signals are received from a data channel, those signals are often degraded to analog signals having uncertain amplitude and non-discernible transitions between logic 1s and 0s. As the logic transitions become difficult to identify, the effects of noise and pulse width distortion adversely affect the system sensitivity and bandwidth.
There is thus a general need in the art for a system and method overcoming at least the aforementioned shortcomings in the art. A particular need exists in the art for a burst mode optical receiver and system and method overcoming disadvantages with respect to signal degradation in deciphering logic transitions, noise and distortion effects in communications networks employing burst mode transmission.